Drop specular lighting from terrain shader — ground materials (dirt, grass,
stone) are purely diffuse and specular highlights made them look plastic.
Replace Reinhard tonemapper with a shoulder-only compressor that is identity
below 0.9 and softly rolls off HDR values above, preserving scene contrast.
Replace hardcoded specular multipliers with uLightColor * uSpecularIntensity
uniforms in all 4 world shaders (terrain, WMO, M2, character), set HDR sun
color (1.5, 1.4, 1.3) and specular intensity 0.5 so highlights can exceed
1.0, and switch the post-process pass from passthrough to exposure-compensated
Reinhard (exposure=1.8) for soft highlight roll-off without clipping.
